Cochlear implants (CIs) have helped many recipients with profound hearing losses to live, learn and work successfully in mainstream environments. Despite their successes, however, many Cl users complain that they encounter significant difficulties hearing and functioning in noisy, reverberant settings. Previous speech perception research has focused on hearing in sound-treated environments with little reverberation. The proposed investigation endeavors to characterize the speech perception abilities of Cl users in natural, reverberant settings and, ultimately, to provide recommendations for maximizing performance in those settings. The specific aims of this investigation are: 1) to determine the impact of reverberation and different types maskers on speech perception when varying numbers of spectral channels of information are available; and 2) to understand the speech perception abilities of Cl users in real-world conditions and to begin to uncover strategies that may improve their function therein. The investigation consists of 6 experiments that determine the individual and interactive effects of reverberation, masking (via speech-spectrum noise and 2-talker babble), distance, and direct/reverberant energy ratios on the intelligibility of simulated and actual Cl processed speech. The first 4 of 6 experiments will model Cl processing with vocoded speech and listeners with normal hearing, using reverberant room simulations to provide strict control over the acoustic characteristics of the environments under study. The fifth experiment will compare the performance of actual and simulated Cl users in simulated rooms. The sixth experiment will evaluate the performance of Cl users in real rooms as they utilize a remote-microphone assistive listening device. The proposed project is the first known research effort to understand and address concerns of Cl users in noisy, reverberant environments. The results of this work will provide fundamental knowledge about both the nature of a Cl user's ability to hear in real-life environments and the effects that reduced access to a complete speech spectrum has on speech understanding in natural environments. This work will ultimately aid in developing habilitative strategies that can improve function within these environments and relieve some of the burden of profound deafness on Cl users in their everyday lives. [unreadable] [unreadable]